The Effect Of Lipoteichoic Acid From Bacillus Subtilis On The Expression Of SBD-1 In Sheep Rumen Epithelial Cells And The Preliminary Study Of Signal Pathway

β-defensin is an endogenous antimicrobial peptide with antimicrobial activity and immunomodulatory activity,which plays an important role in the innate immune system.In this experiment,Lipoteichoic acid（LTA）of Bacillus subtilis was used as an inducer to explore its effect on the expression of sheepβ-defesin-1（SBD-1）in sheep rumen epithelial cells（ORECs）and its signal transduction pathway.In this study,the ORECs in vitro was first cultured,and then the ORECs were stimulated with 0,10,20,30,40 and 50μg·m L^-1Bacillus subtilis LTA for 8 h,respectively.The expression of SBD-1 m RNA and protein in ORECs was detected by quantitative real-time PCR（q PCR）and enzyme linked immunosorbent assay（ELISA）,respectively.Select the best stimulation concentration.The optimal stimulation concentration of Bacillus subtilis LTA was used to stimulate ORECs for 2,4,8,12 and 24 h,respectively.The optimal stimulation time was screened by q PCR and ELISA to determine the optimal stimulation conditions.The results showed that B.subtilis LTA could induce the expression of SBD-1in ORECs,and the optimal stimulation concentration of B.subtilis LTA to stimulate the expression of SBD-1 in ORECs was 10μg·m L^-1,and the optimal stimulation time was 8 h.Then ORECs were stimulated with the optimal stimulation conditions of Bacillus subtilis LTA,and the m RNA expression levels of various pathway factors（TLR-2,My D88,p38,JNK,ERK1/2 and NF-κB）before and after stimulation were detected by q PCR.The changes in the expression of m RNA,thus inferring the signaling pathway involved in SBD-1 signal transduction.The results of the detection of various pathway factors before and after stimulation showed that the expression of SBD-1 induced by Bacillus subtilis LTA in ORECs may be mediated by TLR-2-MyD88-NF-κB and TLR-2-MyD88-MAPK（P38,ERK1/2）signaling pathways.